<!doctype html> 
<html> 
<head> 
    <meta charset="utf-8"> 
    <title></title> 
</head>
<body>
<script type="text/javascript">
function b(x,y,z){
	arguments[2] = 10;
	alert(z);//10

}
b(1,2,3);
alert(arguments[2])//Error

</script>
</body>
</html>